Conventional lateral field effect transistor devices can be of “multi-finger” or “serpentine” form.
In both cases, the source regions are formed as long, thin fingers, which interdigitate with drain regions also formed as long, thin fingers. The source regions extend from source electrodes, and the drain regions extend from drain electrodes. In the multi-finger device, plural gate regions in the form of fingers extend from gate electrodes, each gate region interposing between a source region and a neighbouring drain region. In contrast, in the serpentine device, each gate region extends from a gate electrode to snake around the boundaries between plural neighbouring source and drain regions.
A problem with these conventional devices is that increasing the current rating of the device requires an increase in the lengths and number of the source and drain fingers, which in turn increases resistive and inductive losses.